Note 1 - General and Basis of Presentation - Changes in the Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Beginning balance of the allowance for expected credit losses			$ 597
Ending balance of the allowance for expected credit losses	$ 419		419
Accounting Standards Update 2016-13 [Member]
Beginning balance of the allowance for expected credit losses	597	$ 779	597	$ 755
Change in the provision for expected credit losses for the period	(178)	0	(178)	24
Ending balance of the allowance for expected credit losses	$ 419	$ 779	$ 419	$ 779